This study is a multi - center, single - arm, open - label, phase Ib/II clinical trial for dose exploration and efficacy expansion. The aim is to evaluate the tolerability, safety, pharmacokinetic characteristics, and immunogenicity of the combination regimen of SHR - A1811 in the treatment of platinum - sensitive recurrent epithelial ovarian cancer, determine the recommended phase II dose (RP2D) of the combination therapy, and preliminarily assess its efficacy.